A known lid lock apparatus for retaining a lid member (fuel filler door) which opens and closes a fuel filler lid box which accommodates a fuel filler opening at a closed state is, for example, disclosed in JPH04-302680A (i.e., hereinafter referred to as Patent reference 1). The lid lock apparatus which is mounted to a vehicle body constantly biases a shaft member by a spring and engages a tip end of the shaft member protruding from a housing to the lid member (i.e., a locked position). When refueling, the shaft member is retracted by means of a worm wheel actuated by an electric motor to disengage the shaft member from the lid member (i.e., an unlocked state).
According to the known lid lock apparatus disclosed in the Patent reference 1, a retaining portion shaped in a circular column protrudes from a bottom surface portion of the housing, and a cylindrical stopper member which is made from an elastic member, for example, synthetic resin, is outfitted to the retaining portion. By a contact of a stopper wall provided at a bottom surface of the worm wheel to the stopper member, a rotation of the worm wheel is stopped, thus restricting a movement of the shaft member. The stopper member applied in the known lid lock apparatus disclosed in the Patent reference 1 is simply outfitted to the retaining portion in a press-fitted state. According to the foregoing construction, the stopper member is lifted up relative to the retaining portion because of a deflection (flexure) repeatedly generated at the stopper by the contact of the stopper wall provided at the worm wheel to the stopper member, which may cause a drawback that the retaining portion falls out of the retaining portion. Particularly, in a case where the worm wheel is actuated by a helical gear, the stopper member is likely to be disengaged from the retaining member because the force for pulling out the stopper member is applied every time the stopper wall contacts the stopper member.
JP2010-106438A (i.e., hereinafter referred to as Patent reference 2) discloses a known lid lock apparatus, as shown in FIG. 12, which is devised for preventing the disengagement of the stopper member from the retaining portion. A lid lock apparatus 80 includes a housing 800 which is formed by fitting a body 81 and a cover 82, a worm 84 actuated by an electric motor housed in the housing 800, a worm wheel 85 pivotally supported within the housing 800 and being rotatable in one direction and the other direction by an actuation of the worm 84, and a lock shaft 86 supported within the housing 800 to be axially movable and being engaged with and disengaged from the lid member.
Further, the body 81 includes a retaining portion 81b protruding from a bottom surface portion 81a, and a stopper member 88 is fitted to the retaining portion 81b. A stopper disengagement preventing portion 82b formed in a circular column shape protrudes from an inner surface 82a of the cover 82, and the disengagement of the stopper member 88 from the retaining portion 81b is restricted by a contact of the stopper disengagement preventing portion 82b, which is provided penetrating though an arc shaped slit 85a formed on the worm wheel 85, to an end surface of the stopper member 88.
The worm wheel 85 of the lid lock apparatus 80 disclosed in the Patent reference 2 is formed with the arc shaped slit 85a for allowing an insertion of the stopper disengagement preventing portion 82b. Thus, there is a drawback that the rigidity of the worm wheel 85 is declined.
A need thus exists for a lid lock apparatus which is not susceptible to the drawback mentioned above.